The present invention relates to a touch detection method and a touch detection apparatus using the same.
Sensing methods which are currently being used in touch screens are mostly resistive, surface acoustic wave, and capacitive types. Since the capacitive sensing method makes it possible to sense multiple touches, exhibits excellent durability, visibility, etc., there is a trend toward adopting the capacitive sensing method as a main input means for portable mobile devices.
A capacitive touch screen recognizes a user input by sensing a change in the quantity of electric charge in capacitive sensors on a touch screen panel caused by a user intervention. Capacitive touch sensors are classified into a self-capacitive type and a mutual-capacitive type according to charge accumulation methods. In a self-capacitance touch screen, each capacitive sensor constitutes one conductor and forms a charged surface together with a reference ground outside the touch screen panel, but in a mutual-capacitance touch screen, two conductors on the touch screen panel are configured to mutually form charged surfaces and function as one capacitive sensor.
A general self-capacitance touch screen employs an X/Y orthogonal arrangement of conductors. In this case, each capacitive sensor functions as a line sensor, and thus only one piece of X-sensing information and one piece of Y-sensing information are respectively provided by an X-line sensor group and a Y-line sensor group every time the touch screen is scanned. Therefore, the general self-capacitance touch screen can sense and track a single touch but cannot support multiple touches. A mutual-capacitance touch screen also employs an X/Y orthogonal arrangement of conductors. However, the mutual-capacitance touch screen differs from the self-capacitance touch sensor in that capacitive sensors are each placed at intersections of conductors in the form of grid sensors, and responses of all grid sensors are independently sensed when a user input on the touch screen is detected. Since grid sensors each correspond to different X/Y coordinates and provide independent responses, the mutual-capacitance touch sensor can sense and track multiple touches of a user by extracting user input information from a set of X/Y sensing information provided by a set of X/Y grid sensors.